Dental prophylaxis angles, generally referred to as “prophy angles,” are commonly used dental instruments providing rotation for dental tools such as brushes, prophy cups, or other receptacles used in polishing teeth. A prophy angle typically includes a housing having a neck and a head portion extending at approximately a 90° angle to the neck, which increases the ability of a dentist to reach various surfaces of the teeth of a patient. A drive shaft can be located within the housing and attached to a driven gear in the head of the prophy angle. Prophy angles are generally affixed to a handpiece, which connects the prophy angle to a drive source, thereby enabling a rotating motion of the drive shaft and driven gear of the prophy angle and any affixed dental tool.
Prophy angles are commonly manufactured from lightweight plastic to make them disposable and thereby increasing overall sterility in the dental environment. One drawback of these current instruments is that they are often cumbersome to assemble and may contain a myriad of loosely fitting parts. For example, prior prophy angles have included a two-piece housing which must be mated together prior to use to enclose the inner components of the angle. During use of the prophy angle, the housing may experience increased strain when in contact with the teeth of a patient, and cause the seams in the housing to separate and expose the inner components of the angle. Such separation in the housing may result in a spacing apart or separation of the internal gears of the angle, potentially leading to failure of the device.
In addition to concerns regarding housing integrity, the drive shaft and driven gear of an angle may experience some displacement during use of the prophy angle. As the angle is being used, the drive shaft may excessively move forward or backward due to an increase in the pressure placed on the rotating parts, and result either in an increased amount of force between the gear teeth of the drive shaft and the driven gear, or separation of engagement of the gear teeth of the shaft from those of the driven gear. Subsequently, this displacement can also lead to a premature malfunction of the prophy angle prior to completing a dental procedure.
Furthermore, conventional prophy angles may have a significant amount of contact between surfaces of the housing, the drive shaft and the driven gear. Such large, often flat surfaces can generate increasing amounts of friction as the prophy angle is used at higher rates of rotation. The increased friction can prevent the prophy angle from reaching the desired rate of rotation, may cause enhanced wear and tear between the interacting components, and may generate greater heat, thus making the angle uncomfortable to use.
In light of the above limitations, it would be desirable to provide a prophy angle having a singular housing, where the prophy angle limits displacement of the internal components during use, and further reduces friction between interacting surfaces.